/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.nifi.minifi.nar;

import static java.util.Objects.requireNonNull;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class NarAutoUnloader {

    private static final Logger LOGGER = LoggerFactory.getLogger(NarAutoUnloader.class);
    private final NarAutoUnloaderTaskFactory narAutoUnloaderTaskFactory;

    private NarAutoUnloaderTask narAutoUnLoaderTask;
    private boolean started = false;

    public NarAutoUnloader(NarAutoUnloaderTaskFactory narAutoUnloaderTaskFactory) {
        this.narAutoUnloaderTaskFactory = requireNonNull(narAutoUnloaderTaskFactory);
    }

    public synchronized void start() throws Exception {
        if (!started) {
            narAutoUnLoaderTask = narAutoUnloaderTaskFactory.createNarAutoUnloaderTask();

            LOGGER.info("Starting NAR Auto-Unloader Thread for directory {}", narAutoUnLoaderTask.getAutoLoadPath());

            Thread.ofVirtual().name("NAR Auto-Unloader").start(narAutoUnLoaderTask);

            started = true;
        }
    }

    public synchronized void stop() {
        started = false;
        if (narAutoUnLoaderTask != null) {
            narAutoUnLoaderTask.stop();
            narAutoUnLoaderTask = null;
        }

        LOGGER.info("NAR Auto-Unloader stopped");
    }
}
